60 J. O. HAGSTEOM, CRITICAL RESEARCHES ON THE POTAMOGETONS. 



borg, 84, WiTTROCK (hb. Stockholm.), Malmo, Husie, 65, Brorson (hb. Uppsal. et 

 Lund.), Bjorka, Kropp, 64, Hultberg (hb. Lund.), f. longifolius Fieb., Ousbyholm, 

 hb. Diiben (hb. Lund.), narrow-leaved form, between Rang and Maglarp, 84, Nilsson 

 (hb. Lund.); Uppland, Uppsala, Wieslander (hb. Lund.). — Russia, Livland, Riga, 

 82, Cederwald (hb. Stockholm.). 



Other forms are: 



Var. coriiutlis Linton in The Journ. Bot. 1894, 186. — P. macrorrhyncus 

 Gandog. 1. c, p. p. — P. mspus L. var. macrorrh. (Gdgr) Asch. & Graebn., Syn. 

 1897, 336: — A form with the most elongated rostrum: sThe spur stands out V20 

 in. from the surface of the drupelet, in the dried specimens.* (Linton). 



The length, width, and crispness of the leaves vary. Thus Fieber discerns in 

 V. acutifolius two forms: 



f. Yulgaris: Leaves about 5 cm long, and f. longifolius: Leaves more elongated. 



Var. obtusifolius also sometimes has elongated leaves: thus a forma elongatus. 



The same variety, besides, occurs narrow-leaved, f. angustifolius Fieb, and broad- 

 leaved, f. latifolius Fieb. The former is recorded from Siveden, Scania, Hoganas, hb. 

 Ag. (hb. Lund.) and from Itid. or. Hooker & Thomson (hb. Stockholm, et Lund.); 

 Japan, Tokio, Yatabe (hb. Uppsal.). 



Var. simiatus Fries, Nov. F1. suec. 1828, 43, has the crispest leaves and is 

 besides densly foliated. Two typical examples of this are deposited in the Museum 

 of Uppsala, both from Sweden, Smoland: one from Misterhult lake, labelled hb. Hart- 

 man, and the other from Hemsjon, 1824, E. Fries, labelled: »P. crispus v. crispatus 

 Wallm.». 



Var. najadoides Graebner in Engler, Pflanzenr. IV: 11, 1907, 100: —Leaves 

 very crisp, narrow and more removed from each other. 



Var. planifolius Meyer, Chloris han. 1836, 523: — »Flachblattriges Laich- 

 kraut». P. crispus •( serrulatus (Schrader) Reichb., Icones 1845, 18. — P. crispus 

 v. phialensis Post, Bull. Herb. Boiss. I, 1893, 409? (form with very faint denticula- 

 tion). — 



Var. alatns Zapalowicz might be nothing else than the usual form, see the 

 fig. 2\, F. 



f. liumilis DuMORTiER, Fl. belg. 1827, 163 is individuals of low growth and f. 

 geminifer Reichb., 1. c, individuals with buds (turios). 



Distribution. As to Sweden P. crispus is a southern or south-east species. 

 The most northern outposts of it occur at Hedesunda in Gestricia, 60° 30' N Lat. ; 

 at Karrbo, 55, Cederstrahle (hb. Uppsal.) and Angsjon, 54, Cederstrahle (hb. 

 Stockholm.) in Westmania; at Gotlunda, 58, Blombebg (hb. Lund, et Gotenb.) in 

 Nericia; in Kolungen near Mellerud, Dalia, 84, Fryxell (hb. Stockholm.) and at 

 Kongalf (hb. Lund, et Gotenb.) in Bahusia. — In Norway it is recorded from Ringe- 

 rike. Its most northern limit in the Scandinavian Peninsula, therefore, is a line 

 going from Hedesunda to Orebro and Mellerud in Sweden, to Ringerike, ca. 60° N. 

 Lat., in Norway, nearly corresponding to the year isotherm of + 4° C. It is probable 

 it does not surpass this line in general. In Siberia, however, it goes as far to the 



